Chet Ramey on 30.12.2022 20:51:
Arnold Robbins built on that work and ported the
v8-v10 shells to modern
Linux versions. (I am sorry, I do not have a link right now.)
And btw, 8th ed (
http://man.cat-v.org/unix_8th/1/sh) even added a simple
history mechanism with the "=(1)" command
(
https://www.in-ulm.de/~mascheck/bourne/v8/=.html)
Sven